Method and device for automatic calibration of an odometer

DETAILED DESCRIPTION The present invention provides a method for automatic calibration of a displacement sensor.
The method is advantageous in that automatic calibration of the displacement sensor, for example in the event of a tire change, eliminates the need for laborious manual calibration.
Costs are thereby reduced.
The method is further advantageous in that the displacement sensor is optimally calibrated regardless of vehicle load, tire pressure, or the like.
Dead reckoning location thereby advantageously becomes more reliable.
The present invention also provides for the determination of vehicle speed by receiving satellite signals such as, for example, those transmitted from the Global Positioning System (GPS) system.
At a given speed, the vehicle travels a defined distance within a predefined time period.
The speed can, in this context, advantageously be measured using the Doppler effect.
The distance traveled can then be calculated from the speed.
Even if the GPS data contain a certain error, the present invention contemplates the elimination of systematic error through mathematical techniques.
It is, for example particularly favorable to determine the mean from a plurality of measurements, excluding those values which lie outside a predefined dispersion range.
It appears advantageous in this context to take the standard deviation .
sigma.
as a basis for the dispersion range.
Using the mean and the standard deviation .
sigma.
, the length measurement of an inductive wheel sensor or of a signal from the speedometer sensor can be calibrated within a predefined accuracy.